Composite relay stud



Oct. 13, 1931. R. Ff. MIDDLEKAUFF 1,827,205

COMPOSITE RELAY STUD Original Filed Aug. 50, 1927 Patented Oct. 13, 1931 PATENT OFFICE noBEET PRINDLE MIDDLEKAUFF, or LA GRANGE, ILLiNors, AssIGNOE TO wEsTEENC ELEcTEic coivirANY,l INCORPORATED, E NEW YOEK, N, Y., A oonroEATioN or NEW YORK COMPOSITE RELAY sTUn Original application filed August 30, 1927, Serial No. 216,465.- Divided and this application filed .Tuly 1,1,y ,A

lso

1928. Serial No. 291,917.

This'invention relates to composite articles and more particularly to composite insulating studs for electro-magnetic relays `and thev like.

The present invention is a division of my copending application, Serial No. 216,465, .filed August 30, 1927.` f

In certain types of apparatus and particularly in various classes of electrical apparatus, such as electro-magnetic devices or relays, eX- tensively employed in telephone exchange systems, a plurality of superimposed circuit closing contact springs are operated by al common armature. These springs are arranged in parallelism and in order toaotuate certain of them, insulated stud members orlpins are used which are carried by the movable arma ture of the relay. It has heretofore been the practice in certain instances to useinsulating studs comprising a pair of insulator sleeves which are pressed overV opposite extremities of a metallic core member having a central positioning collar, and obviouslyin thejproe duction of such studs a considerable number of individual forming and assembling operations must be performed to complete the assembly of each stud. Y

The primary obfects'of this invention are the provision of a-rigid anddurable composite article which comprises few and simple parts and which may be economically and expeditiously manufactured. y e l In accordance with the general features of the invention there is provided in one embo'diment thereof a composite relay Astud' comprising a metallic core member 'having a sleeve of insulating material extruded thereon and machined to the desired shape or contour, the core member being provided with a pluraliy of surface indentations whereby theinsulating sleeve isr firmly secured thereto. A I A* f These and other objects and advantages of the invention will be more apparent from the following detailed description when considered in connection with the accompanying drawings, wherein l A Fig. l discloses la fragmentary 'section'al view ofa knurling mechanismwhich is representative of one specific typeV of apparatus which may be employed to formther indentations upon the surface of the metallic core;

Fig. 2 is an enlarged fragmentary detailed view of a knurled core member produced by Vthe mechanism shown in Fig. 1;

Fig. 3 is a fragmentary sectional view of an i extrusion mechanism which may be employed for extruding a covering of insulating mate rialupon the knurled core member shown in Fs 2; j

Fig. 4 is a fragmentary perspective View of a knurled core having a coating of insulating material applied thereto;

Fig. 5 is a fragmentary the compositecylindrica'l stock of the insulating material and vcore member disclosed inFig.'4; 1,

Figi' is a view similar to Fig. 5 with an end portion of the composite cylindrical stock turned down to'form a relay stud;

Fig. 7 is a viewsimilar to Fig. 6 showing a completely formed relay stud at one end of the composite cylindrical stock;

Dfi

detailed view of @fi Fig.8 discloses an insulating stud which 2;

has been COIHDletecl' and severed from the cylindrical stock;

= Fig. 9-is a detailed perspective view of and tional view of a relay of the type employed in telephone circuit whichkis equipped with a unitary stud of the type disclosedinFigs. 8

and 9, a portion; of the relay parts being brovthe numeral 2Oy which comprises, a. pair of opthe completed relaystud disclosedin Fig. V8,

. 10 is a fragmentaryidetailed eleva- E0 positelv disposed knurling cutters 21 rotatablyl mounted within companion blocks 22. Surrounding the cutters 2l and blocks 22 is a casing or housing 24 provided with apertured thimble members 25 which serve to guide a core member 26 which'is passed or drawn between the cutters 2l.k -`When the core member 26 is drawn between these cutters, Opposite surface portions of the core are formed with a plurality of indentatlons or depressions 28 and said core 1s then in condition to .be passed through an extruding mechanism denoted generally by the numeral 29 (Fig. 3)

ing coating 36 of desired thielrnesswhich may subsequently be hardened by any convenient vheat treating or vulcanization process. `Surrounding the core 26 with the uniform covering or coating of insulating material 36 presents la composite cylindrical. s` oclr or rod .which is designated by the numeral 37.

"lhiscomposite cylindrical stock 37 which comprises the 'lmurled core 26 andthe insulating coating 36 applied thereto may now beturned down in a'lathe automatic screw machine or other suitable devices (not shown) so as to present an insulating` stud havingl a desired surface, shape or contour. One extremity of the composite stock shown in Fig. 5 may be turned to form a reduced portion or shank 38 (Fig. 6) and the outer extremity of-this shank 38 is slightly beveled at the point 39. rllhe stoclr37 may be furtherformedby cutting a groove 41 (lig. 7) of desired depth which serves toy present a second reduced portion or shanlr 2 which is oppositely disposed from the shank 38. y making another, cut, the reduced portions 38 and 42 together with a shoulder portion 43ctherebetween may be completely severed from the remaining portion ofthe stock 37. lThese portions 38, 42 and 43 together with the reinforcing core 26 present a completed stud Which isdenoted generally by the numeral 45.

The particular type of insulating` stud 45 disclosed in Figs. 8 and 9 is peculiarly adapted'for use in connection with certain types of electro-magnetic relays 46 (Fig. 10) which are extensively used in telephoneexchange Vsystems for opening and closing electrical circuits. This type of relay includes a group of contact springs 47 which are associated with a relay winding 49. An armature 50 associated with the winding 49 supports the stud 45 in vertical position and is adapted to beswung downwardlyfrom the position shown in'Fig. l0 when the relay is suiiicientenergized. VThe downward swinging of the armature 50 causes the beveled evtremity of the shank 38 to force one of the adjacent contact springs 47 downwardly so as to efiect the contact thereof with a spring positioned immediately therebeneath. The shoulder portion 43 may also engage a contact spring of the relay upon the downward movement of the armature 50. ln order to more fully understand the operating characteristics of the relay 46 reference may be made to the co-pending application of Earl Victor Johnson, Serial No. 183,440, iiled April 13, 1927, wherein this type of relay is described in detail. The relay 46 is merely shown as one example of thepractical application ofthe improved insulating stud and therefore a detailed description of the relay is not believed to be necessary for a complete and thorough understanding of the invention.

From the foregoing it will be understood that a composite part or stud embodying the lfeatures ofthe invention is unitary in structure, comprises few and simple parts, and maybe economically and expeditiously manufactured. It will also be apparent that by extruding the insulating covering upon a core provided with knurled surfaces as described, the core and covering are firmly secured to each other and shifting of the core with respect to the covering is positively precluded.

Although the invention has herein been described in connection with a particular type of composite member or stud used with particular types of electro-magnetic relays, itis to be understood that the invention is capable of many other applications and should be limited only by the scope of the appended claims.

What is claimed is:

1. A composite stud member for electromagnetic relays comprising a core having a surface indentation, and a cylindrical covering of insulating material co-eXtensive with the core and filling the indentation, a p0rtion of said covering material being reduced Vin diameter.

,2. Acomposite insulating stud member for electro-magnetic relays comprising a core member having a plurality of pairs of separated diametrically opposed transverse surface indentations, and a unitary body of insulating material varying in diameter throughout its length and interlocking with the indentations.

3. A composite insulating stud member for electro-magnetic relays comprising a metallic corehaving ,a plurality of surface indentations, and a cylindrical covering of insulating material eXtruding and vulcanized upon the core and filling the indentations, said cylindrical covering having end portions of different diameters, and a central portion of greater diameter than the diameters of the end portions.

4. A composite insulating member for spring Vtype relays comprising a .core member and a unitary covering of insulating material firmly secured thereto, said covering tapered to one end of the core and. having a shoulder for operative engagement with a relay spring.

In Witness whereof, I hereunto subscribe my name this 29th day of June A. D., 1928.

ROBERTPRINDLE MIDDLEKUFF.v y 

